Development of a Method for Manufacturing Easily Removable Ceramic Rods for Lost Waste Casting

The main commercial method of preparing precision metal parts with a high surface finish, for example, the blades of a turbo-ram jet engine, is lost waste casting. On preparing a wax model, a ceramic immuring element (rod) is placed in side the model in order to form cavities of complex shape, intended to reduce the mass of the casting and for forming channel of the cooling system of the blades cooled by the secondary air flow after a rod is removed. The main technological problems on removal of the inner rods are their strength and high chemical inertness, as a result of which their removal time and labor costs are quite large. This article investigates a method of preparing ceramic rods whose strength is not uniform along depth, which makes it possible, first of all, to remove (quite easily) the soft center and then to dissolve the stronger periphery.